1. Field of the Invention
The present invention relates to a reticle and a method for manufacturing a semiconductor device using such a reticle.
2. Description of the Related Art
In the course of manufacturing a semiconductor device, a semiconductor device is subjected to a large number of patterning steps. In the patterning steps, patterns of the semiconductor device are prepared by means of reticles that carry thereon corresponding patterns that are different from each other. Therefore, it is important that the pattern prepared on the semiconductor device in the current step and the pattern prepared on the semiconductor device in a preceding step are aligned relative to each other with an high degree of accuracy.
For the purpose of accurately aligning patterns, an alignment mark for aligning itself with its counterpart formed on the semiconductor device in a preceding step, an alignment-accuracy gauging pattern for gauging the accuracy of alignment or a dimension gauging pattern for gauging the dimension of the prepared reticle is typically formed on a reticle along with a principal pattern to be used for manufacturing the semiconductor device. Such a pattern is made so as to form a profile specifically adapted to the purpose for which it is used. Generally, a pattern that is used for a purpose other than producing a semiconductor device is referred to as an accessory pattern and formed inside a dicing area arranged in a peripheral area of a chip area, i.e., a principal pattern forming region that is cut off when producing a chip.
A prior art reticle has an accessory pattern whose width is much greater than a minimum width of a principal pattern of the chip area. This will be explained later in detail. As a result, a pattern layer formed by the accessory pattern may be peeled off. If this peeling-off phenomenon occurs, it is no longer possible to gauge the accuracy of alignment in a subsequent patterning step and the peeling off of the pattern layer can shed particles in subsequent manufacturing steps, thus reducing the manufacturing yield.
It is an object of the present invention to provide a reticle capable of reducing the peeling-off phenomenon of a pattern layer formed by the reticle.
Another object is to provide a method for manufacturing a semiconductor device by using such a reticle.
According to the present invention, in a reticle for transferring a pattern onto a photosensitive layer by a photolithography process, the reticle has a principal pattern and an accessory pattern, the accessory pattern being divided into a set of continuously arranged sub-patterns.